Hyderabad: World AIDS Day is observed on 1 December ever year to raise awareness of the disease, support people living with it and to commemorate those who have died. Here’s a run-down on the disease:

What is HIV/AIDS?

Acquired immunodeficiency syndrome (AIDS) is a chronic, potentially life-threatening condition caused by the human immunodeficiency virus (HIV). By damaging the immune system, HIV interferes with body’s ability to fight the organisms that cause disease. HIV is primarily a sexually transmitted infection but can also be spread by contact with infected blood or from mother to child during pregnancy, childbirth or breast-feeding. HIV-positive people have a 20 times higher risk of contracting the bacteria that causes tuberculosis (TB). In Africa, TB is the primary cause of death among HIV-infected people.

Can HIV/AIDS be treated?

There’s no cure but there are drugs that can dramatically slow the advance of the disease. Antiretroviral drugs prevent the virus from multiplying in the body. Antiretroviral therapy consists of three or more drugs that the patient has to take for the rest of their lives. Such treatment has reduced the death rate from HIV by around 80%.

According to India HIV Estimation 2015 report released by National AIDS Control Organisation (NACO)—the implementing agency for government’s HIV/AIDS programmes–HIV prevalence in India was estimated at 0.26% (0.22% – 0.32%) in 2015 in the adult population (15–49 years). It was 0.30% among males and at 0.22% among females. Among the states/union territories, Manipur has shown the highest estimated adult HIV prevalence of 1.15%, followed by Mizoram (0.80%), Nagaland (0.78%), Andhra Pradesh and Telangana (0.66%), Karnataka (0.45%), Gujarat (0.42%) and Goa (0.40%). Maharashtra, Chandigarh, Tripura and Tamil Nadu have shown estimated adult HIV prevalence greater than the national prevalence (0.26%).

There were around 2.1 million people living with HIV (PLHIV) in India in 2015. In 2015 an estimated 67,600 people died of AIDS-related causes nationally. Globally there were around 36.7 million people living with HIV by end of 2015, and 1.1 million people died of AIDS-related causes.

What kind of progress has India made in prevention and control?

India launched its National AIDS Control Programme (NACP) in 1992 as a comprehensive programme for prevention and control of HIV/AIDS. The government is spending Rs14,295 crore on NACP IV, partly funded through grants from the Global Fund and credit from the World Bank. NACP IV effective till 2017 aims to reduce new infections and provide comprehensive care and support to all PLHIV and treatment services for all those who require it. The numbers show that India is making steady progress—the adult HIV prevalence at the national level has continued its steady decline from an estimated peak of 0.38% in 2001-03 through 0.34% in 2007 and 0.28% in 2012 to 0.26% in 2015. The total number of PLHIV in India is estimated at 21.17 lakh compared with 22.26 lakh in 2007. India is estimated to have had around 86,000 new HIV infections in 2015, showing 66% decline in new infections from 2000 and 32% decline from 2007. Since 2007, when the number of AIDS related deaths (ARD) started to show a declining trend, the annual number of AIDS related deaths has declined by 54%. In 2015 an estimated 67,600.

What is the state of AIDS vaccine development? What are the challenges vaccine developers are facing?

Developing a vaccine to prevent HIV/AIDS is particularly challenging given that HIV is one of the most complicated viruses ever identified. HIV targets and destroys the very immune system that a vaccine traditionally triggers. HIV mutates aggressively, presenting an endless stream of new forms of the virus that it is unable to recognize and control. Lack of a fully adequate animal model for early testing and private sector vaccine developers, the major disincentive for capital investment in AIDS vaccine research is the fact that the primary markets for a vaccine would be in the poorest countries in the world.

As of today there is no 100-percent-effective vaccine against HIV. However data from a phase III AIDS vaccine trial conducted by the US Military HIV Research Program and the Thai Ministry of Public Health in Thailand showed for the first time that an AIDS vaccine can reduce the risk of HIV infection in humans. According to the International AIDS Vaccine Initiativ, there are around 30 AIDS vaccine candidates undergoing clinical testing in humans, of which at least half-a-dozen are in an advance stage, raising the hopes of a vaccine for the disease.